Lung cancer (LC) is the leading cause of cancer-related deaths worldwide. LC is more frequent in military veterans than in general population, and veterans are considered a high risk population for LC. This project will define in peripheral blood and cancer tissues the specific activities of enzymes that are major mediators of cancer aggressiveness as reliable early detection and prognosis biomarkers of LC. The elevated enzymatic activities will serve as biomarkers of LC early detection by noninvasive screening of peripheral blood of LC high risk populations, and of LC prognosis by testing primary tumors of LC patients. Ultimately, the investigation could lead to a better therapy planning and personalized more successful and economical treatment of early stage LC in veterans and general population. LC high risk populations with chronic obstructive pulmonary disease (COPD), interstitial pulmonary disease (IPD) and small pulmonary nodules (SPN), and LC patients with a localized LC disease will benefit the most from this study. Presently, there are no validated markers or methods for early detection and prediction of LC clinical outcome at the time of initial diagnosis and therapy. Several enzymes produced by cancers, including ADAM10 and ADAM17, have important roles in cancer growth, survival, invasion and metastasis development, and are considered promising cancer biomarkers. The enzymes' gene or total protein expressions have not shown to be reliable or have not been validated as early detection or prediction biomarkers of LC. A specific enzyme activity more directly reflects an enzyme cellular function and, therefore, might be a better cancer biomarker. However, the idea of using enzyme activities as cancer biomarkers has received little attention and has not been evaluated to date. Recently, our laboratory has developed a reliable ADAM sheddase activity (ADAMsa) assay, which detects and measures both ADAM10sa and ADAM17sa (ADAM10sa/17sa). Using this assay, we have demonstrated that head and neck cancer (HNC) contains significantly higher levels ADAM10sa/17sa than normal oral mucosa. More importantly, ADAM10sa/17sa, but not ADAM17 protein expression, are significantly more increased in primary tumors likely to recur relative to those unlikely to recur after therapy. These data are the first to suggest that enzyme activities could be significan cancer biomarkers. Directly pertinent to this proposal, we have developed specific ADAM10sa and ADAM17sa assays, and obtained preliminary data showing that LC patients have selectively increased ADAM10sa in peripheral blood exosomes and LC primary tumor tissues, and ADAM17sa in lung tissues. Importantly, primary tumor tissues of LC patients who died five or more years after initial treatment showed notably higher ADAM10sa/17sa than LC tissues of LC patients who were cancer free during the same time period. Based on these preliminary data and considerations, we hypothesize that LC has prominently increased enzymatic activities of cancer aggressiveness-mediating ADAMs, and that these enzymatic activities may serve as novel clinically useful biomarkers for LC early detection and outcome prediction. This hypothesis will be tested as follows. 1) Validate specific ADAM10sa and ADAM17sa assays. 2) Determine whether ADAM10sa is increased in the blood of LC patients. 3) Demonstrate that high increases of ADAM10sa in primary LC tissues correlate with poor prognosis.